What is the best way to validate a credit card in PHP?
There are three parts to the validation of the card number: PATTERN – does it match an issuers pattern (e.g. VISA/Mastercard/etc.) CHECKSUM – does it actually check-sum (e.g. not just 13 random numbers after “34” to make it an AMEX card number) REALLY EXISTS – does it actually have an associated account (you are unlikely … Read more